Follow @bpolitics for all the latest news, and sign up for our daily Balance of Power newsletter.

A recent survey commissioned by the New York Times found that people who could find North Korea on a map were more likely to favor talks over military action. A glance at North Asia’s geography explains why.

Get the latest on global politics in your inbox, every day.

Get our newsletter daily.

Sign Up

More than six decades after the Korean War ended without a peace treaty, the peninsula remains bisected in a perpetual stalemate, with the U.S.-backed South Korean military lined up against more than a million North Korean troops. While tensions have occasionally flared — such as after Kim Jong Un’s weapons tests or threats of “merciless revenge” over American-led military exercises that began Monday — the two sides have so far staved off another devastating conflict.

The 250-kilometer (160-mile) border defined in a 1953 armistice lays bare one obvious peril of any confrontation: The demilitarized zone sits on the doorstep of the Seoul metropolitan area, where about half of South Korea’s 51 million people live.

North Korea has spent decades concealing hundreds of artillery batteries along the frontier that could wreak havoc in the southern capital, according to Joseph Bermudez, an analyst for the 38 North website run by the U.S.-Korea Institute at Johns Hopkins University’s School of Advanced International Studies. Those weapons could kill thousands of people and damage scores of factories in the time it took the U.S. to project “fire and fury” across the border, as President Donald Trump has warned.

“If all of a sudden artillery rounds started plopping down in the middle of the city, hitting those high-rises, there would be panic like you would not believe,” Bermudez said. “Not only are people killed by direct explosion, they’re killed by all the debris, and they’re killed by accident. You don’t need much artillery to do that.”

After an initial exchange of fire, the danger could quickly engulf the rest of South Korea and neighboring Japan, countries that have been American allies since World War II. More than 80,000 troops are based across the two countries and the U.S. territory of Guam, which would provide key staging areas for any American-led attack.

Those U.S. bases were within reach of Kim’s bombs long before his first successful test of an intercontinental ballistic missile on July 4. Even if Kim still lacks the capacity to outfit those missiles with miniaturized nuclear warheads, he could cause plenty of damage with conventional and chemical weapons.

Kim would probably seek to maximize his advantage against more powerful foes by striking softer civilian targets in places like the greater Tokyo area, which is home to almost 40 million people. At the same time, North Koreans might look to escape the allied onslaught by flooding across the Yalu River to China. The region might also face environmental threats should the U.S. strike Kim’s heavy-water reactor north of the capital Pyongyang, scattering radioactive debris into the atmosphere and groundwater.

Mao Zedong’s decision to back China’s communist neighbors in North Korea was a key reason the U.S.-led United Nations forces were never able to achieve a decisive victory in the Korean War. China’s concern then — that a unified Korea could provide a springboard for attacks on its own territory — remains largely unchanged. And the world’s most populous country would be hard-pressed to remain on the sidelines if a full-fledged conflict erupted on its border.

Unlike his predecessor, Chinese President Xi Jinping commands a nuclear power with one of the world’s most advanced navies and air forces. Should China join a second Korean conflict, that firepower would make it harder for Trump to ensure the safety of the U.S. homeland — much less its bases and allies across Asia.

And don’t forget Russia, which shares borders with China, Japan and North Korea. Russian President Vladimir Putin is already challenging the U.S. in hotspots around the world.

The U.S. is constantly engaging with China and Russia to explain what it would do in a conflict to minimize the chance of an escalation, Bermudez said.